Apparatus for making plastic bags

ABSTRACT

Apparatus is disclosed for making open-gusset bags from overlapping webs of thermoplastic material. A notch-perforator is provided along a side edge of the web for providing sets of notches and perforations or slits at spaced points along the web. V-shaped notches are applied to the gusset portion of the web and then the web is slit and welded transversely to divide the web into bags.

United States Patent [1 1 Davis, Jr.

[ APPARATUS FOR MAKING PLASTIC BAGS [75] Inventor: Francis A. Davis,Jr., Chalfont, Pa.

[73] Assignee: Paramount Packaging Corporation,

Chalfont, Pa.

[22] Filed: Nov. 25, 1970 [21] Appl. No.: 92,735

Related U.S. Application Data [63] Continuation-impart of Ser. No.82,257, Oct. 20,

1970, Pat. No. 3,654,841.

[52] U.S. Cl. 93/33 H, 93/35 SB, 93/D1G. l [51] Int. Cl B31b 1/14, B3lb1/64 [58] Field of Search 93/33 H, 1 G, 58.4,

93/59, 58.5, 58 P, 84 TW, 35 H, 35 SB, DIG. 1

[56] References Cited UNITED STATES PATENTS R26,075 9/1966 Canno 93/58 P3,575,090 4/1971 Hook 93/58.4 X 3,430,528 3/1969 Eddym, 93/58.5 X

[ June 19, 1973 1,931,979 10/1933 Chandler 93/58 P 3,395,622 8/1968Kugler 3,183,750 5/1965 Davis....

3,274,869 9/1966 Piazze...

3,368,441 2/1968 Piazze...

3,561,332 2/1971 ROSS 3,566,756 3/1971 Schmid 3,593,622 7/1971 Sengewald93/84 TW Primary Examiner-Andrew R. Juhasz Assistant ExaminerJames F.Coan Attorney-Seidel, Gonda & Goldhammer [57] ABSTRACT Apparatus isdisclosed for making open-gusset bags from overlapping webs ofthermoplastic material. A notch-perforator is provided along a side edgeof the web for providing sets of notches and perforations or slits atspaced points along the web. V-shaped notches are applied to the gussetportion of the web and then the web is slit and welded transversely todivide the web into bags.

7 Claims, 7 Drawing Figures Patented June 19, 1973 3 Sheets-Sheet 1INVENTOR FRANCIS A. DAVIS. JR.

W I I A TTORNEYS Patented June 19, 1973 3,739,694

3 Sheets-Sheet 2 INVENTOR FRANCIS A. DAVIS. JR.

MM FM ATTORNEYS Patented June 19, 1973 3,739,694

3 Sheets-Sheet 3 INVENTOR FRANCIS A. DAVIS, JR.

ATTORNEYS 1 APPARATUS FOR MAKING PLASTIC BAGS This application isdirected to apparatus of the type disclosed in my U.S. Pat. No.3,282,173 and is a continuation-in-part of my copending patentapplication Ser. No. 82,257 filed Oct. 20, 1970 and entitled Machine forMaking Plastic Bags now U.S. Pat. No. 3,654,841. The disclosures thereinare incorporated herein by reference.

When a web of thermoplastic material is folded so that is overliesitself and has a longitudinally extending fold-line, there are twolayers of material, namely a top layer and a bottom layer. When a gussetis formed along the fold-line, in the gusset there will be four layersof overlapping material. When a notch is cut through the gusset and aweld provided at or parallel to the notch, as disclosed in saidabove-mentioned pending application, the top two layers will be weldedto gether and the bottom two layers will be welded together so as toprovide an open-gusset bag.

The side edges of the top and bottom layers of material, opposite thefold-line, are preferably aligned with one another. At the side edges ofsaid top and bottom layers, the present invention includes a notch andperforator means for applying sets of notches and perforations or slitsat spaced points therealong.

In the above-mentioned patent, the bottom layer projected beyond theadjacent side edge of the top layer by a distance of approximately 1inch so as to provide web material on which spaced sets of perforationsor slits may be applied. The apparatus of the present inventioneliminates the necessity of providing the projecting edge portion on thebottom layer, thereby saving 1 inch of material. At the same time, astronger bag is produced since the entire length of the top and bottomlayers will be welded together.

In accordance with the present invention, the top and bottom layers ofan' intermittently fed web are preferably separated from one anotherandsimultaneously acted upon so that a notch is cut from the top layerand perforations or slits are provided in the bottom layer. During theseportions of the processing time period wherein the web is stationary,the side edges of the web are notched and perforated, the gusset portionof the web is notched with welds being applied at or adjacent to thenotches in the gusset, and one bag is separated from the web by acutter-welder means.

It is an object of the present invention to provide apparatus for makingplastic bags wherein the top and bottom layers at the open end of thebag will have at least one notch in the top layer and at least oneperforation or slit in the juxtaposed portion of the bottom layer.

It is another object of the present invention to provide apparatus andmethod for making bags or the type disclosed in U. S. Pat. No. 3,184,055without the necessity of a projecting portion for receiving the slits orperforations as disclosed in said patent.

It is another object of the present invention to provide apparatus formaking plastic bags having a notch and perforator means which is simpleand reliable.

For the purpose of illustrating the invention, there is shown in thedrawings a form which is presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIG. 1 is a top plan view of the apparatus of the present invention.

FIG. 2 is a side elevation view of the notch and perforator'means takenalong the line 2-2 in FIG. 1.

FIG. 3 is a sectional view taken'along the line 33 in FIG. 2 with thecomponents thereof in an inoperative disposition.

FIG. 4 is a sectional view similar to FIG. 3, but showing the componentsin an operative disposition.

FIG. 5 is a sectional view taken along the line 5-5 in FIG. 2.

FIG. 6 is a partial exploded view of a bag made in accordance with thepresent invention and the portions removed from the web by the notch andperforator means.

FIG. 7 is a partial plan view of another bag which may be made with theapparatus of the present invention.

Referring to the drawing in detail, wherein like numerals indicate likeelements, there is shown in FIG. 1 a top plan view of the apparatus inaccordance with the present invention designated generally as 10. Theapparatus 10 is intended to have fed therethrough a pair of spacedparallel thermoplastic webs 12 and 14. The apparatus 10 has two parallelproduction lines, each defined by one of the webs. The webs l2 and 14are processed in the same manner except for the fact that one of thewebs is upside down with respect to the other.

The web 12 is folded along fold-line 16 so that it overlies itself. Web14 is similarly folded along line 18. Since each of the webs isprocessed in the same manner, only the processing of web 12 will bedescribed in detail hereinafter. It will be understood thatcorresponding structure is utilized in conjunction with web 14.

The web 12 is continuously unwound from large rolls and fed through acapstan take-up roll assembly 20. When forming fold-line 16, the toplayer 22 and the bottom layer 24 overlie one another. Preferably,neither the top layer nor the bottom layer protrudes beyond the otherlayer along a side edge of the web opposite the fold-line l6.

Along the fold-line 16, there is provided a rotatable gusset plate 26which forms a gusset along the fold-line 16. A similar gusset plate 28is provided which forms a gusset along the fold-line 18. The gussetplates are of the type disclosed in the above-mentioned patent. Anyconventional means may be utilized to intimately feed the web 12 andoperate the machine 10.

A notch and perforator means 30 is provided for notching and perforatingor slitting the side edge of the web 12 opposite the fold-line 16. Asimilar means 32 is provided for the web 14. Since the printing on thelayers of the web 14 is upside down from those on web 12, the means 32is upside down with respect to the means 30. Otherwise, the webs 12 and14 are processed identically.

The notch and perforator means 30 provides a notch 31 on the top layer22 and a pair of perforations 33 in the exposed portion of the bottomlayer 24. The manner in which this is accomplished will be described ingreater detail hereinafter.

Downstream from the notch and perforator means 30, there is providedadjacent the gusset on webs l2 and 14, a notch and welder means 34 forproviding V- shaped notches 36 in the gusset at spaced points therealongand correlated with respect to the position of the notches 31. The means34 is preferably of the type disclosed in my above-mentioned copendingapplication. Means 34 provides a similar V-shaped notch at the gusset ofweb 14. Downstream from the means 34, there is provided a cutter andwelder means 38 for web 12 and a similar means 40 for web 14. The means38 and 40 cut the webs transversely and provide a weld at or along thecut so as to divide the webs into bags 42. Means 38 and 40 may be of thetype disclosed in the above-mentioned patent wherein the seam weld is atthe transverse cut or may be of the type wherein the seam weld is spacedfrom but adjacent to the transverse cut as disclosed in my copendingapplication Ser. No. 775,748 filed Nov. 14, 1968 entitled Method andApparatus for Making Plastic Bags, now US. Pat. No. 3,555,974.

The notch and perforator means 30, as shown more clearly in FIGS. 2-5,includes a vertical wall 42 having a top wall 44, a bottom wall 46 and aseparator wall or die plate 50, 50. Hence, the frame defined by thesewalls is E-shaped. The separator wall 50, 50' extends between the toplayer 22 and the bottom layer 24 of the web 12. The components 50 and 50are spaced from one another so as to define a gap 49 and each of thecomponents is bolted to the wall 42.

A shoulder 52 is mounted on the wall 44. Conduits 54 and 56 are coupledto the cylinder 52 to facilitate supply and exhaust of motive fluid tothe cylinder 52. The motive fluid is preferably air. A piston disposedwithin cylinder 52 is connected to the upper end of a piston rod 58.

The piston rod 58 extends through a bore in wall 44 and a bore in aplate 60. A bolt 62 is connected to the free end of the piston rod 58with the plate 60 held against a shoulder on the piston rod 58. Plate 60is guided with respect to the wall 44 by means of guide rods 63extending through bushings on the wall 44.

Plate 60 is an actuator plate. First and second web retainers 64 and 66are coupled to the actuator plate with a lost motion connection as willbe made clear hereinafter. The web retainers 64 and 66 are spaced fromone another so as to define a gap which is wider than gap 49 andoverlies gap 49. A blade 68 having a serrated cutting edge at the lowerend thereof is bolted to a blade support member 72. Support member 72 isfixedly secured to a bottom surface on the actuator plate 60. Blade 68is aligned with the gap 49 and extends between the web retainers 64 and66. Web retainer 66 is provided with a notched portion 67 so as toaccommodate the blade support member 72 as shown more clearly in FIG. 4.

A plurality of posts 74 are secured at their lower ends to the webretainer 64 and extend through a bore in the actuator plate 60. A spring76 surrounds each post 74 and biases the web retainer 64 away from theactuator plate 60 until a head 78 at the upper end of the posts 74engages a shoulder surrounding the bore in plate 60.

The web retainer 66 is similarly coupled to the actuator plate 60 bymeans of posts 74 having an enlarged head 78' at their upper ends andsprings 76 surrounding the posts 74'.

The coupling between actuator plate 60 and the web retainers 64 and 66is a lost motion connection since the upward movement of the actuatorplate 60 is not directly translated to upward movement of the webretainers 64 and 66 until after the heads 78, 78' contact a shoulder onplate 60. The lowermost surface on the web retainers 64 and 66 arepreferably provided with a rubberized coating which contacts the toplayer 22 before, during and after notching to prevent stretching thelayer 22.

A front wall 80 is attached to the horizontally disposed bottom wall 46and extends upwardly therefrom. The wall 80 is parallel to the wall 42and connected thereto by side walls 84 and 86. The upper edge of walls80, 84 and 86 is spaced from the separator wall 50, 50. Wall 80 isprovided with a notch 82 extending downwardly from its uppermost edgefor purposes to be made clear hereinafter.

A cylinder 88 is secured to the wall 46 and depends therefrom. A pistonwithin cylinder 88 is connected to one end of a piston rod 90. A spring,not shown, surrounds the piston rod 90 within the cylinder 88 and biasesthe piston in cylinder 88 downwardly.

The upper end of piston rod 90 is adjustably connected to a horizontallydisposed mounting plate 92. Plate 92 is notched and guided forreciprocal vertical movement by a guide 94 bolted to the wall 42. A pairof cylindrical perforators 96 and 98 having a serrated edge 100 at theiruppermost end is supported by the mounting plate 92. A blade 102 havingan angularly disposed cutting edge is supported by the mounting plate92. The blade 102 is directly behind the perforator 96 and lies in avertical plane which contains the axis of the cylindrical perforator 96.The vertical plane is perpendicular to the wall 42. A similar blade 104is associated with the perforator 98 in a similar manner. Bolts extendthrough elongated slots in the blades 102 and 104 so as to facilitatevertical adjustment of the angularly disposed cutting edge on theseblades with respect to the mounting plate 92.

As shown more clearly in FIG. 5, the separator wall 50 is provided witha hole 106 through which the perforator 96 may extend in its uppermostdisposition as shown in FIG. 4. A slot 108 extends from the hole 106 tothe rear edge of the separator wall 50. The blade 102 extends throughthe slot 108.

The separator wall 50' is provided with a second hole designated 106through which the perforator 98 may extend. A slot 108, similar to slot108, extends from the hole 106. The blade 104 is adapted to extendthrough the slot 108'.

The notch 31 on the bag 42 is cut from the top layer 22 by the blade 68.As shown in FIG. 6, the notch 31 includes a bight parallel to the edgedefining the open end of the bag and converging side portions extendingfrom the open end of the bag and inwardly from the side edges of thebag. In this manner, the top layer 22 may be welded to the bottom layer24 along the entire length of the side edges 109 on the bag 42. Thisprovides for a stronger bag which is less susceptible to being tornalong a welded side edge 109.

When the elements shown in FIG. 3 move from the inoperative dispositiontherein to the operative disposition shown in FIG. 4, the tab 116 is cutout of the top layer 22 by the blade 68, thereby producing the notch 31,two disks 114 are produced as the holes 33 are cut by the perforators 96and 98, and the slits and l 12 are produced by the blades 102 and 104.Due to the flimsy nature of polymeric material such as polyethylene orpolyurethane, and the static electricity involved, a positive means mustbe provided to remove the scrap in the form of the tab 116 and the disks114. Such means includes an opening 118 in the wall 42 aligned with aconduit 120 connected to a source of vacuum. Hence, the scrap will besucked into the conduit 120 and discharged into a scrap container.

In order to remove the disks 114 from within the cylindrical perforators96 and 98, means are provided for blowing the disks upwardly so thatthey may be sucked into the conduit 120. The air inlet conduit 122 forintroducing air into the cylinder 88 is connected by a T- coupling toconduits 124 and 126. Conduit 124 communicates with the interior ofperforator 96. Conduit 126 communicates with the interior of perforator98. The slots 82 in the wall 80 accommodate the conduits 124 and 126 aswill be apparent from a comparison of FIGS. 3 and 4.

As air is introduced into cylinder 88 to move the piston rod 90upwardly, a check valve in the T-coupling prevents air from beingintroduced into the bottom of the perforators 96 and 98 by way of theconduits 124 and 126. On the return stroke of piston rod 90, the checkvalve opens and cylinder 88 exhausts into conduits 124 and 126. Theserrations 100 at the upper end of the perforators 96 and 98 facilitateholding the disks 114 at the upper end of the perforators and thedischarge of the pressurized air from within the perforators until thedisks may be sucked into conduit 120 by way of the opening 118.

In view of the above, it is not deemed necessary to set forth a detailedsequence of operations. Each time the web 12 stops, means 30, 34 and 38perform a function on the web 12 simultaneously. As soon as the web 12stops moving, the components of means 30 move from the position shown inFIG. 3 to the position shown in FIG. 4 and then return to the positionshown in FIG. 3. The separator wall 50, 50 at all times extends betweenthe top and bottom layers 22 and 24 of the web 12.

The introduction of a motive fluid through conduit 54 into cylinder 52causes the actuator plate 60 to descend from the position shown in FIG.3. Air is simultaneously introduced into cylinder 88 to move the pistonrod 90 upwardly from the position shown in FIG. 3. Blade 68 extends intothe gap 49 and cuts the notch 31. Perforators 96 and 98 move upwardly tocut the holes 33 in the bottom layer 24.

When conduit 54 is exhausted and motive fluid introduced through conduit56, the piston rod 58 moves upwardly from the position shown in FIG. 4.This causes the actuator plate 60 to move upwardly with the piston rod58 until the heads 78 and 78 engage the shoulder in actuator plate 60.Thereafter, the web retainers 64 and 66 move upwardly with the actuatorplate 60. Until the heads 78 and 78' bottom out in the actuator plate60, the web retainers 64 and 66 do not move upwardly.

The retainers 64 and 66 remain in the position shown in FIG. 4 withtheir rubberized surface holding the top layer 22 against the uppermostsurface on the separator wall 50, 50' until the blade 68 has beenwithdrawn. After the web retainers 64 and 66 have moved upwardly, thevacuum coupled to conduit 120 sucks the tab 116 and the disks 114 intothe conduit 120 through the opening 118. The piston rod 90 descends tothe position shown in FIG. 3 before the web 12 commences movement sothaf the process may be repeated along the length of theweb 12. It will benoted that the web retainers 64 and 66 engage the top layer 22 of theweb 12 and hold the same firmly in position before the blade 68 passesthrough the web and into the gap 49.

This assures a good clean out without any puckering or stretching of thetop layer 22.

As shown in FIG. 6, the notch 31 is of sufficient size so as to have alength greater than the distance between the pair of holes 33. Ifdesired, a pair of notches 31 may be cut from the top layer 22, witheach of the notches 31 overlying the area of the holes 33' as shown moreclearly in FIG. 7 wherein there is illustrated a partial plan view of abag 42 which may be made utilizing the present invention. Thus, thepresent invention may be utilized to produce one or more notches in thetop layer 22 and the notches may be of varying configurations. In orderto cut the notches 31, a pair of curved blades 68 will be utilized withcorresponding gaps 49 being provided in the separator wall The cuttingblade 68 which notches the top layer 22 and the perforators 96 and 98are preferably on opposite sides of the web 12. Mounting and operationof the blades and perforators are easily facilitated for purposes ofinstallation, actuation and maintenance when so constructed. It would bewithin the scope of the invention to mount the perforators 96 and 98 onthe same side of the web 12 as the cutter blade 68, with the result thatthe tab 1 12 will be perforated when producing the perforations 33 inthe bottom layer 24.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

I claim:

1. A machine for making bags from thermoplastic material comprisingmeans for intermittently feeding a web having a top and bottom layerconnected along a longitudinal edge by a gusset, a notch welder meansfor cutting a V-shaped notch in the gusset while the web is stationaryand simultaneously providing a seam weld adjacent the notch, said seamweld joining the top two layers of the gusset together and also joiningthe bottom two layers of the gusset together, means downstream from saidnotch welder means for transversely cutting the stationary web at theapex of the notch to form individual bags and simultaneously seam-weldthe cut edges, and a notch and perforator means upstream from the notchwelder means for notching the top layer along an edge remote from saidgusset and perforating a juxtaposed portion of the bottom layer of theweb.

2. A machine in accordance with claim 1 wherein said notch andperforator means includes a notching blade movable toward and away fromthe top layer, a pair of perforators movable as a unit toward and awayfrom the bottom layer for providing spaced perforations in the bottomlayer, and means for retaining the top layer firm to prevent stretchingof the top layer while it is being notched.

3. A machine in accordance with claim 2 wherein said notch andperforator means includes a separator wall adapted to extend into thespace between said top and bottom layers, said separator wall having agap into which the notching blade extends.

4. A machine in accordance with claim 2 wherein said notch andperforator means includes an actuator plate connected to said notchingblade, said retaining means including first and second web retainers onopposite sides of the blade and spaced from one another for cutting adisk from the bottom layers and blades for slitting the bottom layerfrom an edge of the bottom layer, each slit extending toward one of theholes produced by the cutting of the disks.

7. A machine in accordance with claim 1 including means on the oppositeside of the web with respect to the notch and perforator means forforming a gusset in the juxtaposed edge of the web along a center lineof the web, said gusset forming means being upstream from said notchwelder means.

1. A machine for making bags from thermoplastic material comprisingmeans for intermittently feeding a web having a top and bottom layerconnected along a longitudinal edge by a gusset, a notch welder meansfor cutting a V-shaped notch in the gusset while the web is stationaryand simultaneously providing a seam weld adjacent the notch, said seamweld joining the top two layers of the gusset together and also joiningthe bottom two layers of the gusset together, means downstream from saidnotch welder means for transversely cutting the stationary web at theapex of the notch to form individual bags and simultaneously seam-weldthe cut edges, and a notch and perforator means upstream from the notchwelder means for notching the top layer along an edge remote from saidgusset and perforating a juxtaposed portion of the bottom layer of theweb.
 2. A machine in accordance with claim 1 wherein said notch andperforator means includes a notching blade movable toward and away fromthe top layer, a pair of perforators movable as a unit toward and awayfrom the bottom layer for providing spaced perforations in the bottomlayer, and means for retaining the top layer firm to prevent stretchingof the top layer while it is being notched.
 3. A machine in accordancewith claim 2 wherein said notch and perforator means includes aseparator wall adapted to extend into the space between said top andbottom layers, said separator wall having a gap into which the notchingblade extends.
 4. A machine in accordance with claim 2 wherein saidnotch and perforator means includes an actuator plate connected to saidnotching blade, said retaining means including first and second webretainers on opposite sides of the blade and spaced from one another sothat the blade may pass therebetween, said web retainers having a lostmotion connection with respect to said actuator plate.
 5. A machine inaccordance with claim 2 wherein said notch and perforator means includesa separator wall adapted to enter the space between said top and bottomlayers, said notching blade being supported above said separator wall,said perforators being supported below said separator wall.
 6. A machinein accordance with claim 1 wherein said notch and perforator meansincludes perforators for cutting a disk from the bottom layers andblades for slitting the bottom layer from an edge of the bottom layer,each slit extending toward one of the holes produced by the cutting ofthe disks.
 7. A machine in accordance with claim 1 including means onthe opposite side of the web with respect to the notch and perforatormeans for forming a gusset in the juxtaposed edge of the web along acenter line of the web, said gusset forming means being upstream fromsaid notch welder means.